DRU-385 - Bound chat history, name untitled threads, and park send/stop on the gate

backend/druks/contrib/chat/models.py

@@ -1,3 +1,4 @@
+from collections.abc import Sequence
 from datetime import datetime
 
 from sqlalchemy import ForeignKey, select
@@ -7,6 +8,10 @@
 from druks.contrib.chat.schemas import ConversationSummary
 from druks.db import Base, StoredSubject, db_session
 
+_PROMPT_MESSAGES = 40
+_PROMPT_CHARS = 16_000
+_TITLE_CHARS = 80
+
 
 class Conversation(StoredSubject):
     __tablename__ = "chat_conversations"
@@ -67,9 +72,31 @@ async def save_autonomy(self, autonomy: Autonomy) -> None:
         self.autonomy = autonomy
         await db_session().flush()
 
+    async def name_from_first_line(self) -> None:
+        """Fill an empty title from the first user line. A title the operator
+        already set, or a prior call, is left alone."""
+        if self.title:
+            return
+        first = next(
+            (message for message in await self.list_messages() if message.role == Role.USER),
+            None,
+        )
+        if not first:
+            return
+        line = next(
+            (" ".join(raw.split()) for raw in first.body.splitlines() if raw.strip()),
+            "",
+        )
+        if line:
+            self.title = line[:_TITLE_CHARS]
+            await db_session().flush()
+
     async def list_messages(self) -> list["Message"]:
         return await Message.list_for_conversation(self.id)
 
+    async def list_prompt_messages(self) -> list["Message"]:
+        return Message.bound_recent(await self.list_messages())
+
     def get_summary(self) -> ConversationSummary:
         return ConversationSummary.model_validate(self)
 
@@ -115,3 +142,19 @@ async def list_for_conversation(cls, conversation_id: int) -> list["Message"]:
             .order_by(cls.created_at, cls.id)
         )
         return list(await db_session().scalars(statement))
+
+    @classmethod
+    def bound_recent(cls, messages: Sequence["Message"]) -> list["Message"]:
+        """Newest lines that fit the prompt. Older lines drop first. One
+        oversize last line still goes in — truncating it would hide the turn
+        the operator just sent."""
+        chosen: list[Message] = []
+        chars = 0
+        for message in reversed(messages):
+            size = len(message.body)
+            if chosen and (len(chosen) >= _PROMPT_MESSAGES or chars + size > _PROMPT_CHARS):
+                break
+            chosen.append(message)
+            chars += size
+        chosen.reverse()
+        return chosen

backend/druks/contrib/chat/templates/talk.md

@@ -1,4 +1,4 @@
-You are this operator. Act through the live Druks MCP catalog.
+Act on behalf of the signed-in operator. Use the attached MCP tools to inspect and change this appliance.
 
 Discover work with list_open_subjects. Echo parkedAt from get_gate unchanged when you answer a gate. Do not invent run ids.
 

backend/druks/contrib/chat/workflows.py

@@ -26,8 +26,8 @@ class ChatTurn(Gate):
     would offer approve/request_changes on a chat turn."""
 
     name = "chat_turn"
-    text: str
-    stop: bool = False
+    action: Literal["send", "stop"]
+    note: str = ""
 
 
 class ConfirmTool(Gate):
@@ -78,31 +78,38 @@ class Talk(Workflow):
     async def run_multistep(self) -> None:
         while True:
             conversation = await self.subject
-            messages = await conversation.list_messages()
+            messages = await conversation.list_prompt_messages()
             result = await Chat.reply(
                 autonomy=conversation.autonomy,
                 messages=[{"role": message.role, "body": message.body} for message in messages],
             )
             await self.record_message(Role.ASSISTANT, result.text)
+            await self.name_thread()
             deferred = await self.deferred_writes()
             if deferred:
                 decision = await ConfirmTool.wait(
                     input_request={
                         "presentation": "in_app",
                         "label": "Confirm the proposed action",
                         "controls": ["approve", "reject"],
+                        "questions": [],
                     },
                     hold_sandbox=self.sandbox_hold,
                 )
                 if decision.action == "approve":
                     await self.apply_deferred_writes(deferred)
             reply = await ChatTurn.wait(
-                input_request={"presentation": "in_app", "label": "Chat turn"},
+                input_request={
+                    "presentation": "in_app",
+                    "label": "Message",
+                    "controls": ["send", "stop"],
+                    "questions": [],
+                },
                 hold_sandbox=self.sandbox_hold,
             )
-            if reply.stop:
+            if reply.action == "stop":
                 return
-            await self.record_message(Role.USER, reply.text)
+            await self.record_message(Role.USER, reply.note)
 
     async def get_workspace_kwargs(self, host: "Host") -> dict[str, Any]:
         conversation = await self.subject
@@ -120,6 +127,11 @@ async def record_message(self, role: Role, body: str) -> None:
         conversation = await self.subject
         await conversation.add_message(role=role, body=body)
 
+    @step
+    async def name_thread(self) -> None:
+        conversation = await self.subject
+        await conversation.name_from_first_line()
+
     @step
     async def deferred_writes(self) -> list[dict[str, str]]:
         return await OperatorToken.take_deferred(self.workflow_id)

backend/tests/chat/test_models.py

@@ -75,3 +75,69 @@ async def test_get_for_account_misses_another_operators_thread():
     assert (await Conversation.get_for_account(mine.id, owner.id)).id == mine.id
     assert await Conversation.get_for_account(theirs.id, owner.id) is None
     assert await Conversation.get_for_account(mine.id, None) is None
+
+
+async def test_name_from_first_line_fills_an_empty_title():
+    account = await Account.get_or_create("op@example.com")
+    conversation = await Conversation.create(account_id=account.id, title="")
+    await conversation.add_message(role=Role.USER, body="  Pump the tires  \nmore detail")
+    await conversation.add_message(role=Role.ASSISTANT, body="ok")
+
+    await conversation.name_from_first_line()
+
+    assert conversation.title == "Pump the tires"
+
+
+async def test_name_from_first_line_leaves_an_operator_title():
+    account = await Account.get_or_create("op@example.com")
+    conversation = await Conversation.create(account_id=account.id, title="Pump")
+    await conversation.add_message(role=Role.USER, body="something else")
+
+    await conversation.name_from_first_line()
+
+    assert conversation.title == "Pump"
+
+
+async def test_name_from_first_line_caps_a_long_first_line():
+    account = await Account.get_or_create("op@example.com")
+    conversation = await Conversation.create(account_id=account.id, title="")
+    await conversation.add_message(role=Role.USER, body="x" * 100)
+
+    await conversation.name_from_first_line()
+
+    assert conversation.title == "x" * 80
+
+
+async def test_name_from_first_line_is_idempotent():
+    account = await Account.get_or_create("op@example.com")
+    conversation = await Conversation.create(account_id=account.id, title="")
+    await conversation.add_message(role=Role.USER, body="first")
+    await conversation.name_from_first_line()
+    await conversation.add_message(role=Role.USER, body="later")
+
+    await conversation.name_from_first_line()
+
+    assert conversation.title == "first"
+
+
+async def test_prompt_history_keeps_the_newest_lines():
+    account = await Account.get_or_create("op@example.com")
+    conversation = await Conversation.create(account_id=account.id, title="t")
+    for index in range(41):
+        await conversation.add_message(role=Role.USER, body=f"m{index}")
+
+    prompt = await conversation.list_prompt_messages()
+
+    assert [message.body for message in prompt] == [f"m{index}" for index in range(1, 41)]
+    assert [message.body for message in await conversation.list_messages()][0] == "m0"
+
+
+async def test_prompt_history_drops_older_lines_that_overflow_the_char_budget():
+    account = await Account.get_or_create("op@example.com")
+    conversation = await Conversation.create(account_id=account.id, title="t")
+    await conversation.add_message(role=Role.USER, body="a" * 10_000)
+    await conversation.add_message(role=Role.ASSISTANT, body="b" * 10_000)
+
+    prompt = await conversation.list_prompt_messages()
+
+    assert [message.body[0] for message in prompt] == ["b"]

backend/tests/chat/test_pages.py

@@ -96,7 +96,12 @@ async def test_a_parked_turn_puts_gate_controls_on_the_thread(druks_client, druk
         subject=conversation,
         state="parked",
         input_gate=ChatTurn.name,
-        input_request={"presentation": "in_app", "label": "Chat turn"},
+        input_request={
+            "presentation": "in_app",
+            "label": "Message",
+            "controls": ["send", "stop"],
+            "questions": [],
+        },
     )
     run.input_requested_at = datetime.now(UTC)
     await druks_db.flush()

backend/tests/chat/test_prompts.py

@@ -0,0 +1,20 @@
+from druks.prompts import render_prompt
+
+
+async def test_talk_prompt_carries_autonomy_bounded_history_and_mcp_discovery():
+    rendered = await render_prompt(
+        "chat/talk.md",
+        autonomy="propose",
+        messages=[
+            {"role": "user", "body": "hello"},
+            {"role": "assistant", "body": "hi"},
+        ],
+    )
+
+    assert "Act on behalf of the signed-in operator" in rendered
+    assert "list_open_subjects" in rendered
+    assert "parkedAt" in rendered
+    assert "Do not invent run ids" in rendered
+    assert "Autonomy: propose" in rendered
+    assert "user: hello" in rendered
+    assert "assistant: hi" in rendered